Zac Goldsmith appears to have told his Richmond Park association he is going to quit and call a by-election:

Heathrow Announcement: A Note to Members

Dear Member,

You will no doubt have seen the announcement in the media this morning that the Government has given the green light for expansion at Heathrow.

Zac has contacted the Association to let us know that he intends to honour his pledge to resign and force a by election in Richmond Park.

The Chairman has called an Emergency Meeting of Executive Council for tomorrow evening to discuss this turn of events and will issue a full statement to members on the Associations position on Thursday.